STOCK AWARD PLANS - Employee Stock Purchase Plan Activity (Details) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares purchased by employees (shares)	42,445
Aggregate cost to employees	$ 3,699,626
Expense recognized by the company	10,776,000	$ 8,850,000	$ 33,127,000	$ 40,657,000
Company expense on ESPP discount
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recognized by the company	$ 652,875	$ 551,000	$ 2,272,000	$ 2,320,000

Number of shares issued during the period as a result of an employee stock purchase plan.

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration